Sheet metal bending machine with offset press rollers

ABSTRACT

The invention features a sheet metal bending machine constituted by a smooth carrying roller around which the sheet metal is rolled, after bending, and by smooth press rollers against which the carrying roller presses, is characterized in that the carrying roller (2) is supported at one end by a fixed bearing (15) and at its other end by a retractable bearing (18), and in that the press rollers (3, 4) are supported, directly or indirectly (support rollers) by a plurality of bearings (5) supported by a control mechanism called &#34;inclined blocks&#34;. (7, 8).

BACKGROUND OF THE INVENTION

This invention falls within the domain of working with sheets ofmaterial, such as sheets of metal, with a view to bending them, morespecifically the object of the invention is a machine, called a "bendingmachine", designed to bend the sheets of metal.

Patent FR-974.789 (BIGWOOD° describes a bending machine for sheet metalwith a pivoting upper support roller and a retractable bearing; howevera machine like this uses a complex mechanism for adjusting the radius ofthe bend by means of a motor driven screw.

The Applicant's patent FR-2.528.334 describes a bending machine with apivoting support roller, and in this respect it is similar to the abovementioned device, this pivoting support roller is situated above a pairof two smooth rollers with a smaller diameter, called pressers, parallelto each other and able to be moved away from each other in order toproduce different bending radii; the performance of these machines wasnot as good as that of the preceding machines but they were cheaper andwere suitable for boiler making concerns where the bending constitutedonly one part of the job. The present invention relates specifically torollers like these.

Patents FR-2.528.335 and FR-2.637.206 belonging to the same Applicantdescribe bending machines said to have toothed rollers consisting of abig roller called a support roller and two sets of numerous rollerscalled pressers with sufficiently small diameter relative to that of thesupport roller and interlocking with each other so that they are able tohave lines of contact with the support roller, closer than thosepermitted by full rollers, in order to increase the accuracy of thebending and to reduce to a minimum the parts remaining straight at theextremities of the sheet on entry to and exit from the bendingoperation; in this type of machine the toothed rollers, situated abovethe big roller, are grouped in two parallel trains of rollers each trainitself being composed of several coaxial rollers; in certain machines ofthis type, determination of the bending radius is carried out by varyingthe distance between the presser rollers (toothed) and the supportroller, using an inclined plane device (sloped cams and wedges) whichcan be moved by sliding one against another by means of a crank with agravitational indicator dial. These machines, with high productivity andgreat ease of handling, are generally used by specialist concerns in theseries production of ferrules (sheets of metal bent and welded).

These machines have a common characteristic in that the presser andsupport rollers always remain parallel; however in the case of thinsheets (for example thinner than 2 millimeters) or of soft material (forexample aluminium) they have the disadvantage of "marking" the sheet asa result of the toothed nature of the presser rollers.

The aim of the present invention is to make a bending machine availableto non-specialist concerns which will permit the bending of quite largesheets, that are not very thick, and/or made of a material that is notvery hard.

SUMMARY OF THE INVENTION

According to the present invention a machine for bending sheets, calleda bending machine, of the type of bending machine consisting principallyof a roller, called a support roller, around which the sheet is to berolled after bending, and smooth rollers, called pressers, designed topress against the support roller is characterised in general

in that the support roller around which the sheet is rolled afterbending, is connected at a first extremity to a motor and is supportedat this first extremity by a fixed bearing, and at its other extremityby a retractable (swivel) bearing, the axis of this support rollerremaining fixed, and

in that the presser rollers are smooth rollers arranged in pairs with afixed distance between axes and supported by a number of bearings, orrollers, themselves supported by a beam which rests on the frame bymeans of inclined wedges

It is therefore in the new combination of known means, and in theestablishment of the effectiveness of such a combination, for thepurpose of achieving a result, namely the bending of soft and/or thinsheets, with the facility of making rapid and accurate changes to thebending radius, that the inventive nature must be sought, rather than inthe novelty of the means taken independently.

The fixed axis support roller is preferably placed above the assembly ofpresser rollers so that the presser rollers can be moved vertically upand down by the inclined wedges when they are pressed against the sheetthat is to be bent, and down as a result of their weight after thebending operation.

The result of this arrangement is that the bending radius can becontrolled simply by reading the marking on the gravitational indicatordial for the means of adjustment and that, in general, passing the sheetonly once between the rollers is sufficient to bend it to the desiredextent, it will, however, be noted that the operator will always havethe choice between bending the sheet in one passage between the rollersor several, bearing in mind that it is the bending machine that willdetermine the accuracy of the bending and not the operator.

At this stage of the definition of the invention it will be noticed thatthere are two difficulties to be resolved: one relates to theflexibility of the presser rollers, the other to the flexibility of thesupport roller.

The first lies in the fact that,

because the lines of contact of the presser rollers with the supportroller can be quite close to each other, relative to the size of thediameters of the presser rollers, so that a sheet introduced between thefirst presser roller and the support roller, comes into oblique contactwith the upper segment of the second presser roller,

it is necessary that the diameter of the presser rollers be much smaller(about 1/3) than the diameter of the support roller, and that theserollers be as close as possible to each other; now considering that theresistance of a cylindrical beam to sagging varies roughly by the fourthpower (D⁴ ) of its diameter, their small diameter will result in greatflexibility, in practice unacceptable flexibility, of the presserrollers.

In order to define the ideas raised above, more accurately, by "as closeas possible" there is meant the fact that the distance between theiraxes e lies between d and 1,5d, d being the diameter, preferably thesame for each one, of the presser rollers, d itself lying between0,2xDand 0,5xD, D being the diameter of the support roller the effectivelength of D lying between 5xD and 10xD, the smallest bending diameterthat can be achieved with a machine as defined being between about 1,2and 1,4xD: it will be noted that the choice of these dimension ratiosalso enhances the invention because of the innumerable theoreticpossibilities which it offers a great number of which prove to beinappropriate in practice, which only an intuitive judgement based onwide experience can eliminate a priori.

One solution proposed by the invention to solve the problem of thesagging of the presser rollers, consisted of dividing the presserrollers into sections, each section being supported in rotation at itsextremities, by a support component, the support components themselvesresting on a beam, preferably and I-beam, called intermediate, itselfsupported indirectly on the general frame of the machine.

However, because the rollers are in sections, the problem of "marking"of the sheets by the extremity edges of the sections, remained to besolved; this problem was resolved by wedging the sections in the axialdirection, so that the extremity edge of one section of a presser rolleris always opposite a cylindrical part of a section of the other roller,excepting for the extremities of the rollers themselves; the withdrawingwedge chosen is only slightly bigger than the thickness of the supportcomponents, this thickness is reduced to a minimum by the judiciouschoice of the suspension of the sections, and as a result of theZ-configuration of the support components; with the result that evenvery thin sheets can be bent without being marked.

All that remains to be resolved for a machine like this is the problemof sagging, albeit only slight, in the support roller, and also that ofdetermining the bending radius; a solution that has already been appliedin another type of machine (cf: FR-2.637.206, FIG. 6 and 7)), has beenadapted to the bending machine of the invention, namely the insertionbetween the non-flexible general frame and the beam supporting thepresser rollers of a mechanism with a "ramp of cams" and with "slopedwedges", the surfaces in contact with the cams and sloped wedges beingplanes which with the plane of the axes of the presser rollers, formdihedral angles with their crests oblique relative to these axes; itwill be recalled that it is the slope of the wedges and their transversedisplacement that permits compensatory adjustment of the sagging of thesupport roller; in the new application which has been carried out, themechanism is inserted under the presser rollers, between the beam whichsupports these rollers and the frame.

The assembly of these combined arrangements, namely presser rollers withreduced distance between the axes, adjustment of the bending radius bymeans of a ramp of cams and sloped wedges, and adjustable stop withgraduated dial, permits accurate adjustment by an unqualified operator,and bending achieved in a single passage through the rollers resultingin high productivity.

A second solution proposed by the invention more particularly adapted tobending with a small radius, but always bearing in mind the problem ofsagging, consisted of adding a second stage of rollers with smalldiameters to the presser rollers divided into sections supported inrotation, these second stage rollers with small diameter positionedabove the preceding presser rollers and also supported by the sameZ-configured support components.

Finally a third solution proposed by the invention, more particularlyadapted to bending thin and fragile sheets (thickness <0.6 mm), thesecond stage rollers are continuous over the whole width of the passageof the sheets, and rest either on sectioned rollers with Z-shapedsupport components, or more simply on wheels distributed over the widthof the passage and supported by ordinary support components.

It must therefore be understood that the bending machine of theinvention is represented as the assembly resulting from the combination

of permanent characteristics of the support roller and its components ofcompensation for sagging, feeding and maintaining, and means formanoeuvring the presser rollers, and

alternative characteristics roughly three in number, of actual presserrollers and their means of support

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood, and the improvementswill appear from the description which will be made of the solutionsproposed by the invention, with reference to the attached plates andfigures in which:

FIG. 1 is a side elevation of a bending machine according to theinvention including, as an example of this, the first and secondcharacteristics, these characteristics being an improvement on the firstsolution for presser rollers,

FIG. 2 is a section along AA of the bending machine shown in thepreceding figure, illustrating on a larger scale the arrangement anddimensional ratios of the various rollers,

FIG. 3 is a plan drawing on a larger scale of the constructivearrangement of the presser rollers and their support components,

FIG. 4 is a perspective drawing of a bearing from the preceding figure,and

FIG. 5 is a partial view in exposed perspective of the bending machineshown in FIG. 1,

FIG. 6 is a diagram of a transverse section of a bending machinefeaturing the second solution for the presser rollers,

FIG. 7 is a section along AA of the preceding figure

FIG. 8 is a perspective drawing of a bearing from the preceding figure,and

FIG. 9 is a simplified perspective drawing of the rollers of a bendingmachine featuring the third solution for the presser rollers, and

FIGS. 10 and 11 show, seen end on, the presser rollers of the precedingfigure with their supporting wheels and their extremity supportcomponents FIG. 10) and intermediate support components (FIG. 11), and

FIG. 12 shows, in a direction perpendicular to that of the precedingfigures, how the support wheels fit on to their support component.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIGS. 1 and or 2, a bending machine according to the invention isprincipally made up of a frame consisting of a massive I-shapedframe-beam 1, an upper roller with large diameter D, called supportroller 2, in the direction of which two sets 3, 4 of rollers with smalldiameters, called presser rollers, can be drawn upwards, each of thesesets consisting of several roller sections; the presser rollers aresupported by means of support components such as 5 by an I-beam calledintermediate beam 6.

The intermediate beam 6 can be moved vertically, between the extremityguides 26, by a manoeuvring device of the ramp type 7 with inclined camsand wedges 8 supported by the frame beam 1; the ramp 7 is movedhorizontally by a couple of jacks such as 9; adjustment of the amplitudeof vertical displacement of the support beam thus the space between thepresser rollers and the support roller, space which determines thebending radius, is achieved by horizontal displacement of a stop 10, bymeans of a manually rotated screw 11 with a gravitational indicator dial12.

The support roller 2 is supported at a first extremity 13, from where itis rotated by an hydraulic motor 14, by a very robust first bearing 15two diameters in length, and at its other extremity 16 by a retractablebearing 17 fitted into a swivel component called a "side gate" 18; thisarrangement permits axial retraction of the sheets after bending

With reference to FIGS. 1 or 2, the following dimensional sizes arefixed

d: diameter of the presser rollers (113 mm)

e: distance between the axes of the presser rollers (120 mm),

D: diameter of the support roller (310 mm),

L: efficient length of the support roller (2080 mm);

it will be noted that the dimensions given between brackets are those ofa particular bending machine, that they correspond with the ratiosdefined above, and that they should in no way be considered to limit thescope of the invention.

In FIGS. 3 and 4, the presser rollers each consist of numerous sections31, 32, 33 . . . of equal length, and it will be noted that neighbouringextremities of four adjacent sections are supported by one commonsupport component, such as 51, consisting of a thin Z-shaped partition53 forming with the sole 54 a corner piece, this arrangement confers aparticularly high rigidity on the support component, which allows thepartition to be of the desired thinness and permits two adjacentextremities of two sections of the same roller to be as close to eachother as possible and thus only to have to unwedge two opposite rollers,for example 31 and 41, for a minimal distance 1.

Because of the thinness of the partition which does not allow for thecreation of bearings for supporting rotation of a hub, the rollersections are each made of a hollow cylinder, such as 44 shown insection, mounted to rotate on a coaxial central shaft 45 by bearingssuch as 46 situated in the vicinity of each of the extremities of thesection; the shaft itself being engaged securely in a hole 57 reamed outfrom the adjacent partition 53 of a support component 5 (FIG. 4); eachreamed out hole, excepting for those of the extremity support componentsof the rollers thus supports two neighbouring coaxial shafts.

In FIG. 5, certain components from the preceding figures are show againwith the same reference numbers; it will be noted moreover that theinclined wedges such as 8 can be moved obliquely relative to the camramp 7 and the intermediate beam 6 which supports them by means of anoblique stand that has a slide (see FIG. 6 of the patent mentionedabove), cranks of gravitational indicator dials with cranks such as 24and 25, analogous to the crank 12 mentioned above, which each permitdisplacement of the respective inclined wedge, such as 8, to which it isconnected, so that the sagging of the support roller can be compensatedfor depending on the thickness or the nature of the sheet to be bent.

The ramp 7 itself can be moved by pushing with a couple of hydraulicjacks such as 9 using a transverse component called a "stirrup" 23, towhich the ramp is connected.

The side gate 18 with bearing 17 is articulated on to the frame 1 sothat it can swivel (arrow 19) when subjected to the effects of a jack 20between a vertical position in which the bearing 17 fits on to theconical extremity 16, of the support roller 2, and a horizontal position(not shown) in which the extremity of the roller is free so that thebent sheet can be extracted. It will be noted that the conical shape,even rounded shape of the extremity 16 of the support roller, permitsthe axis of this support roller to remain fixed while the side gate ismoved, even while the bent sheet is being extracted.

The jack 20 for the side gate, the jacks 9 for moving the ramp 7 and thehydraulic motor 14 for driving the support roller 2 are supplied withpressurised fluid by a common hydraulic centre not shown but which isadvantageously secured close to the extremity of the general frame wherethe motor is.

Thus as a result of the means of adjustment consisting principally ofthe gravitational dials, the operator, who needs no particularqualification, has only to set the various adjustments from anempirically established table, to achieve the desired bending.

It will be noted that, still within the scope of the invention, thehydraulic motor can be replaced by a simple electric reduction motor orby an electric motor with a "brushless" type of axle, and the hydraulicjacks by ball screws and axle motor; it may also be noted that themanual manoeuvring device for the means of adjustment can be replaced byan assembly that is under numeric control so that the bending radius canbe varied in a programmed fashion while a single sheet is passingthrough the bending machine, and in this way a ferrule is finallyachieved that is oval, elliptical or polygonal with rounded angles.

In FIG. 6, a roller illustrating the second solution is shown, having alower stage of rollers such as 31, with axes 31', there are three ofthem and they serve as support for the two presser rollers 32, with axes32', with small diameter and quite close to each other, which aresituated above them.

From FIG. 7 it can be seen that a roller 32 from the preceding figure isa solid roller while a support roller 31 is mounted on ball bearings ona fixed axle 33; the rollers 31 and 32 are supported by Z-shaped supportcomponents such as the component in FIG. 8, analogous to that of FIG. 4,showing the axes 31' and 32' of the rollers.

FIG. 7 shows clearly that the rollers, both pressers 32 and support 31,of the bending machine shown in FIGS. 6 to 8 are discontinuous sections.

In FIG. 9, the presser rollers 42, according to the third solution, andas opposed to those of the preceding figures, are continuous, that isthey extend over the entire width of the passage of the sheets, alongthe length of the bending machine; the rollers 42 are supported atintervals by pairs of wheels such as 43 positioned every so often alongan intermediate support component such as 44, or on one side of anextremity support component such as 45.

Finally it will be noted that the machine can have means for automaticvariation of the bending radius during the rolling operation, and soproduce ferrules (bent sheets) with noncircular profiles (for exampleelliptical, triangular with rounded angles, etc. . . . ).

What is claimed is:
 1. Machine for bending metal sheets, called a bending machine, of the type of bending machine which consists principally of roll, called a support roll (2), in an upper position, the support roll comprising an axis and a first end (13) and a second end (16), said support roll around which the sheet is to be rolled after bending, said support roll being, supported at its second end (16), by a retractable bearing (17) so that the rolled sheet can he extracted by moving it along the axis of the support roll and of lower rolls, called presser rolls (3,4) intended to press the sheet against the support roll,the support roll (2) around which the sheet is rolled after bending, being connected, at its first end (13), to a motor (14) and being supported at this first end by a fixed bearing (15), the axis of the support roll remaining fixed, characterized:in that the presser rolls (3,4) are arranged in pairs with fixed distances (e) between their axes and are supported by numerous bearings (5), or rolls (31), themselves supported by a beam (6) which itself rests on the frame (1) via a manoeuvring device with a ramp of cams (7) and "sloped wedges" (8).
 2. Bending machine according to claim 1, characterized:in that the presser rolls (3, 4, 32) are divided into sections (31, 32, 33, . . . ), each section being supported for rotation, at its ends, by a support component (5, 51, 52, . . . ), the support components themselves resting on the intermediate beam (6), and in that the sections (31, 32, 33) of one roll are offset relative to those (41, 42, 43) of the other roll in the axial direction, and are supported by support components (51) consisting of a Z-shaped thin partition (53) forming an angle-bracket-shaped assembly with a sole (54), so that the end edge of one section of a presser roll is always opposite a cylindrical part of a section of the other roll, except for the ends of the rolls themselves.
 3. Bending machine according to claim 2, characterized:by a second stage of presser rolls (32) of small diameter positioned above rolls or wheels.
 4. Bending machine according to claim 3, characterized:in that the rolls of the second stage are sections themselves also supported by the same Z-shaped support components (51).
 5. Bending machine according to claim 3, characterized:in that the rolls (42) of the second stage are continuous over the entire sheet passage width.
 6. Bending machine according to claim 5, characterized:in that the rolls of the second stage rest on sectioned rolls with Z-shaped support components (51).
 7. Bending machine according to claim 5, characterized:in that the rolls of the second stage rest on wheels (43) distributed over the passage width and supported by ordinary support components (44).
 8. Bending machine according to either one of claims 2 and 3, characterized:in that the distance e between the axes of the presser rolls (3, 4) is between d and 1.5d, d being their diameter, preferably identical for each one, d itself being between 0.2D and 0.5D, D being the diameter of the support roll (2), the effective length L of the latter itself being between 5D and 10D.
 9. Bending machine according to claim 8, characterized:in that the sections of the roll each consist of a hollow cylinder (44) mounted so as to rotate on a coaxial central shaft (45) via rolling bearings (46) positioned in the vicinity of each of the ends of the section, the shaft itself being engaged securely in an open bore (57) in the adjacent partition (53) of a support component (5), each bore, except for those in the support components for the ends of the rolls, supporting two neighbouring coaxial shafts.
 10. Bending machine according to claim 1, characterized:in that the support roll is supported at a first end (13) by a double-length first bearing (15) and at its other end (16) by a retractable bearing (17) made in a tiltable component (18) called a gate, and in that the gate (18) with the bearing (17) is articulated to the frame (1) so that it can tilt (arrow 19), under the effect of a jack (20), between a vertical position, in which the bearing (17) fits snugly on a tapered end (16) of the support roll (2), and a horizontal position in which the end of the roll is free so that the bent sheet can be extracted.
 11. A machine for bending metal sheets comprisinga frame (1); a support roll (2) including an axis, a first end (13), a second end (16), and disposed in an upper position, wherein a sheet having been bent is to be rolled around the support roll; a fixed bearing (15) disposed on the frame and supporting the first end of the support roll, wherein the fixed bearing (15) retains the axis of the support roll in a fixed position; a maneuvering device having a ramp of cams (7) and "sloped wedges" (8) and disposed on the frame (1); a beam (6), wherein the beam (6) rests on the manoeuvring device having a ramp of cams (7) and "sloped wedges" (8); a plurality of members selected of the group consisting of pressure bearings (5) and bearing rolls (31), wherein individual ones of the plurality of members selected of the group consisting of pressure bearings (5) and bearing rolls (31) are supported by the beam (6); a plurality of pressure rolls (3, 4) disposed below the support roll, wherein individual rolls of the plurality of pressure rolls each have an axis and are aligned with the axes disposed in parallel positions, and wherein individual ones of the plurality of pressure rolls (3,4) are disposed in pairs having fixed distances (e) between their axes, wherein individual ones of the plurality of pressure rolls (3,4) are supported by individual ones of the plurality of members selected of the group consisting of pressure bearings (5) and bearing rolls (31); a retractable bearing (17) supporting the support roll at the second end (16) of the support roll for extracting the rolled sheet by moving the rolled sheet along the axis of the support roll and along the axis of the plurality of pressure rolls for pressing the sheet against the support roll; a motor (14), wherein the motor (14) is connected to the first end (13) of the support roll (2), around which the bent sheet is rolled.
 12. The bending machine according to claim 11 whereinthe pressure rolls (3, 4, 32) are subdivided into sections (31, 32, 33, . . . ), wherein each one of the sections is supported at its ends, by a support component (5, 51, 52, . . . ) for allowing rotation, and wherein the support components themselves resting on the beam (6); wherein the sections (31, 32, 33) of one roll are offset relative to those sections (41, 42, 43) of the other roll in the axial direction, and wherein the sections are supported by support components (51) consisting of a Z-shaped thin partition (53) forming an angle-bracket-shaped assembly with a sole (54), whereby the end edge of one section of a pressure roll is always opposite a cylindrical part of a section of the other roll, except for the ends of the rolls themselves.
 13. The bending machine according to claim 12 further comprisinga second stage of pressure rolls (32) of small diameter positioned above rolls or wheels.
 14. The bending machine according to claim 13, wherein the rolls of the second stage are sections which in turn are also supported by the same Z-shaped support components (51).
 15. The bending machine according to claim 13, wherein the rolls (42) of the second stage are continuous over the entire sheet passage width.
 16. The bending machine according to claim 15, wherein the rolls of the second stage rest on sectioned rolls with Z-shaped support components (51).
 17. The bending machine according to claim 15, wherein the rolls of the second stage rest on wheels (43) distributed over the passage width and supported by ordinary support components (44).
 18. The bending machine according to claims 12, wherein the distance e between the axes of the pressure rolls (3, 4) is between d and 1.5d, wherein d is the diameter of the pressure rolls, wherein d has a value of between about 0.2D and 0.5D, wherein D is the diameter of the support roll (2), and wherein the effective length L of the support roll (2) is between 5D and 10D.
 19. The bending machine according to claim 18, wherein each of the sections of the roll consists of a hollow cylinder (44) mounted allowing for rotating on a coaxial central shaft (45) via roller bearings (46) positioned in the vicinity of each of the ends of the section, wherein the shaft itself is engaged securely in an open bore (57) in the adjacent partition (53) of a support component (5), wherein each bore, except for those bores in the support components for the ends of the rolls, is supporting two neighboring coaxial shafts.
 20. The bending machine according to claim 11, wherein the support roll is supported at the first end (13) by a double-length first bearing (15) and at the second end (16) by the retractable bearing (17) made in a tiltable component furnished by a gate (18), and wherein the gate (18) with the bearing (17) is articulated to the frame (1) so that it can tilt (arrow 19), under the effect of a jack (20), between a vertical position, in which the bearing (17) fits snugly on a tapered end (16) of the support roll (2), and a horizontal position in which the end of the roll is free so that the bent sheet can be extracted. 